The invention relates to a mixing apparatus having a container for the mixing of media as well as to a container for such a mixing apparatus.
Solutions and suspensions are frequently produced in the pharmaceutical industry and in the biotechnological industry which require a careful mixing of the components. Examples for this are the deactivation of viruses by a huge change in the pH or the production of buffers. Processes in bioreactors in which especially grown microorganisms or cells are cultivated in a culture medium under conditions which are as ideal as possible to obtain either the cells themselves, e.g. tissue cells, or parts thereof or their metabolic products, also frequently require a careful mixing of the cell cultures with gases.
All these processes share the feature that they very frequently have to be carried out under sterile conditions to avoid contamination of, for example, the grown tissue. Such processes have therefore usually been carried out in stainless steel tanks, glass tanks or chromium tanks which have previously been sterilized in a complex and/or expensive manner. The trend has been emerging more and more in recent times to carry out such processes in flexible plastic bags which are intended for single use only. Such bags are frequently already sterilized in manufacture and are supplied to the customer in a sterile packaging. Examples for such bioreactors for single use only can be found in WO-A-2005/118771 or in WO-A-2005/10476.
Mixers or agitators are provided in the vessels for the mixing of the components. Since the processes are frequently carried out under a controlled atmosphere, that is, in vessels which are closed with respect to the environment, the lead-through of the rotating axles into the vessel represents a possible source of contamination, for example also due to abrasion in the slide seal rings of the shaft. Furthermore, microorganisms can collect in the lead-throughs which put the sterility at risk, for example. These problems can be avoided or solved in that the agitating member or mixing member is magnetically coupled to a rotary drive located outside the vessel. Such a solution is proposed for example, in U.S. Pat. No. 7,086,778.
It is also frequently very difficult to ensure a homogeneous and gradient-free mixing of the different components when using agitators or mixers. Flows with different turbulences arise due to the mixers, with the turbulences as a rule being substantially more pronounced in the proximity of the mixers than in regions which are far away from the mixers. This has the consequence that a homogeneous mixing only arises very slowly—if at all. The invention intends to find a remedy here.